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Old 04-26-07, 01:10 PM   #1
Camilo
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Ultegra Brake Quick Release problem

I was having a problem with the quick release on my Ultegra (6500?) rear brakes. When I turned the quick release lever, the anchor bolt rotated with the lever - the anchor bolt was cranking the cable 90 degrees, and NOT returning the brakes to the correct position. It is supposed to work with the lever moving a cam mechanism which raises and lowers the anchor bolt, not twisting it. It looked like it was simply torqued too tight, gunked up or both.

It looked like a simple mechanism, so I took it apart, and really it is a simple straight forward deal, except...

The only problem is that there is a tiny ball bearing in there that nests in a little spring in the quick release lever itself. The purpose of the ball bearing is to create "detents" when the lever is moved. Inside the mechanism there is a serrated bushing that works with the spring loaded ball bearing to make the detents.

It can be seen in the assembly labeled "17" in this diagram: http://tinyurl.com/2jjt9u (this is the exploded view of the Ultegra 6500 brake from the Shimano.com site)

Incidently - this part and assembly is also shown on the exploded view of the DuraAce brakes.

Anyway, I could not get the lever to push into the bushing with the ball bearing in place. To do this, the ball bearing needs to to retract into the spring, and it doesn't do it on it's own (at least with the amount of force I'm willing to put on it).

I did get the mechanism back together without the ball bearing, and it works fine - rotating smoothly and the quick release works fine in full-open and full-closed positions. But the detents aren't there. I'm thinking there must be some reason for the detents - probably so the quick release doesn't inadvertantly release and/or so that intermediate positions (between full-open and full-closed) will hold in place.

Does anyone have any words of wisdom -either "don't worry about it" or advice on how to assemble it with the ball bearing.

NOTE: although I tried VERY HARD to loose that ball bearing (it is TINY), I managed to find it every time I dropped it and now have it sealed in a large envelope)
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Old 04-26-07, 08:40 PM   #2
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The spring isn't that stiff. It's probably hanging up on something when you try to "collapse" it. I don't have any tricks since I've never done the re-assembly. Maybe contact Shimano?
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Old 04-26-07, 10:18 PM   #3
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Originally Posted by DMF
The spring isn't that stiff. It's probably hanging up on something when you try to "collapse" it. I don't have any tricks since I've never done the re-assembly. Maybe contact Shimano?
Thanks. I think I'll take it apart again (it's easy to get back together w/o the ball bearing) and see if I can actually extract the spring and free it up. It did seem like the spring was compressing, and seemed like it should just compress when the lever was inserted w/ ball bearing. But maybe it's getting hung up, maybe just binding in the little channel it rests in. .....

edit: Well, I just removed and cleaned up the spring and then finessed it in, compressing the ball into the spring with a tiny screwdriver blade. Everything is working great.... in case anyone is interested.

Last edited by Camilo; 04-27-07 at 12:58 AM.
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Old 04-27-07, 06:01 PM   #4
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